The present invention relates to vane operating mechanisms and more particularly to a lever arrangement for simultaneously actuating vanes in stator vane rows of a gas turbine engine.
Variable stator vanes are utilized in fans, compressors, and turbines of many gas turbine engines. The actuating mechanisms for these vanes conventionally include various operable combinations of levers, gears and articulated joints cooperating to rotate each vane about its rotation axis and driven by a unison ring or gear. In this respect, each row of variable stators is typically provided with a unison or actuation ring which, when rotatably moved, effects a concurrent rotatable movement of a vane through the interconnected actuating mechanism. The conventional vane actuating mechanisms are relatively complex in manufacturing, assembly and operation, and are subject to wear due to friction at joints thereof.
In the design of an advanced gas turbine engine it would be desirable to provide a new and improved vane actuating mechanism as provided by the present invention. The invention has particular utility when applied to tandenm variable stator vanes wherein a stationary stator vane row is typically provided upstream of a rotating blade row for suitably guiding airflow thereto. The tandem vane rows include two axially adjacent vane rows, instead of the one typically found in the prior art, to provide increased airflow guiding ability without undesirable performance losses therefrom which would otherwise occur in a single vane row rotated to relatively large guiding angles.